function [lnVcoef DlnVcoef] = Vcoef(lnV,var_poly)

lnVcoef = (var_poly\lnV)';
DlnVmat = zeros(6,6);
DlnVmat(2,1) = 1;
DlnVmat(3,4) = 1;
DlnVmat(4,2) = 2;
DlnVmat(5,6) = 2;
DlnVmat(6,3) = 1;
DlnVmat(6,5) = 1;
DlnVcoef = lnVcoef*DlnVmat;
DlnVcoef = reshape(DlnVcoef,3,2);
